Creutzfeldt-Jakob disease (CJD) is a rare, degenerative, invariably
fatal brain disorder.
It affects about one person in every one million
people per year worldwide; in the United States there are about 200 cases
per year.
CJD usually appears in later life and runs a rapid course.
Typically, onset of symptoms occurs about age 60, and about 90 percent of
patients die within 1 year. In the early stages of disease, patients may
have failing memory, behavioral changes, lack of coordination and visual
disturbances. As the illness progresses, mental deterioration becomes
pronounced and involuntary movements, blindness, weakness of extremities,
and coma may occur.

There are three major categories of CJD:

In sporadic CJD, the disease appears even though the person has no
known risk factors for the disease. This is by far the most common type of
CJD and accounts for at least 85 percent of cases.

In hereditary CJD, the person has a family history of the disease
and/or tests positive for a genetic mutation associated with CJD. About 5
to 10 percent of cases of CJD in the United States are hereditary.

In acquired CJD, the disease is transmitted by exposure to brain or
nervous system tissue, usually through certain medical procedures. There
is no evidence that CJD is contagious through casual contact with a CJD
patient. Since CJD was first described in 1920, fewer than 1 percent of
cases have been acquired CJD.

CJD belongs to a family of human and animal diseases known as the
transmissible spongiform encephalopathies (TSEs). Spongiform refers to the
characteristic appearance of infected brains, which become filled with
holes until they resemble sponges under a microscope. CJD is the most
common of the known human TSEs. Other human TSEs include kuru, fatal
familial insomnia (FFI), and Gerstmann-Straussler-Scheinker disease (GSS).
Kuru was identified in people of an isolated tribe in Papua New Guinea and
has now almost disappeared. Fatal familial insomnia and GSS are extremely
rare hereditary diseases, found in just a few families around the world.
Other TSEs are found in specific kinds of animals. These include bovine
spongiform encephalopathy (BSE), which is found in cows and often referred
to as "mad cow" disease, scrapie, which affects sheep and goats, mink
encephalopathy, and feline encephalopathy. Similar diseases have occurred
in elk, deer, and exotic zoo animals.

CJD is characterized as a rapidly progressive dementia. Initially,
patients experience problems with muscular coordination; personality
changes, including impaired memory, judgment, and thinking; and impaired
vision. People with the disease also may experience insomnia, depression,
or unusual sensations. CJD does not cause a fever or other flu-like
symptoms. As the illness progresses, the patients' mental impairment
becomes severe. They often develop involuntary muscle jerks called
myoclonus, and they may go blind. They eventually lose the ability to move
and speak and enter a coma. Pneumonia and other infections often occur in
these patients and can lead to death.

There are several known variants of CJD. These variants differ somewhat
in the symptoms and course of the disease. For example, a variant form of
the disease — called new variant or variant (nv-CJD, v-CJD), described in
Great Britain and France — begins primarily with psychiatric symptoms,
affects younger patients than other types of CJD, and has a longer than
usual duration from onset of symptoms to death. Another variant, called
the panencephalopathic form, occurs primarily in Japan and has a
relatively long course, with symptoms often progressing for several years.
Scientists are trying to learn what causes these variations in symptoms
and course of the disease.
Some symptoms of CJD can be similar to symptoms
of other progressive neurological disorders, such as Alzheimer's or
Huntington's disease. However, CJD causes unique changes in brain tissue
which can be seen at autopsy. It also tends to cause more rapid
deterioration of a person's abilities than Alzheimer's disease or most
other types of dementia.

There is currently no single diagnostic test for CJD. When a doctor
suspects CJD, the first concern is to rule out treatable forms of dementia
such as encephalitis (inflammation of the brain) or chronic meningitis. A
neurological examination will be performed and the doctor may seek
consultation with other physicians. Standard diagnostic tests will include
a spinal tap to rule out more common causes of dementia and an
electroencephalogram (EEG) to record the brain's electrical pattern, which
can be particularly valuable because it shows a specific type of
abnormality in CJD. Computerized tomography of the brain can help rule out
the possibility that the symptoms result from other problems such as
stroke or a brain tumor. Magnetic resonance imaging (MRI) brain scans also
can reveal characteristic patterns of brain degeneration that can help
diagnose CJD.

The only way to confirm a diagnosis of CJD is by brain biopsy or
autopsy. In a brain biopsy, a neurosurgeon removes a small piece of tissue
from the patient's brain so that it can be examined by a neuropathologist.
This procedure may be dangerous for the patient, and the operation does
not always obtain tissue from the affected part of the brain. Because a
correct diagnosis of CJD does not help the patient, a brain biopsy is
discouraged unless it is needed to rule out a treatable disorder. In an
autopsy, the whole brain is examined after death.
Both brain biopsy and
autopsy pose a small, but definite, risk that the surgeon or others who
handle the brain tissue may become accidentally infected by
self-inoculation. Special surgical and disinfection procedures can
minimize this risk. A fact sheet with guidance on these procedures is
available from the NINDS and the World Health Organization.

Scientists are working to develop laboratory tests for CJD. One such
test, developed at NINDS, is performed on a person's cerebrospinal fluid
and detects a protein marker that indicates neuronal degeneration. This
can help diagnose CJD in people who already show the clinical symptoms of
the disease. This test is much easier and safer than a brain biopsy. The
false positive rate is about 5 to 10 percent. Scientists are working to
develop this test for use in commercial laboratories. There have been
reports of other ways of diagnosing the disease, including tonsil
biopsies, which may lead to other tests.

There is no treatment that can cure or control CJD. Researchers have
tested many drugs, including amantidine, steroids, interferon, acyclovir,
antiviral agents, and antibiotics. However, none of these treatments has
shown any consistent benefit.

Current treatment for CJD is aimed at alleviating symptoms and making
the patient as comfortable as possible. Opiate drugs can help relieve pain
if it occurs, and the drugs clonazepam and sodium valproate may help
relieve myoclonus. During later stages of the disease, changing the
person's position frequently can keep him or her comfortable and helps
prevent bedsores. A catheter can be used to drain urine if the patient
cannot control bladder function, and intravenous fluids and artificial
feeding also may be used.

Some researchers believe an unusual "slow virus" or another organism
causes CJD. However, they have never been able to isolate a virus or other
organism in people with the disease. Furthermore, the agent that causes
CJD has several characteristics that are unusual for known organisms such
as viruses and bacteria. It is difficult to kill, it does not appear to
contain any genetic information in the form of nucleic acids (DNA or RNA),
and it usually has a long incubation period before symptoms appear. In
some cases, the incubation period may be as long as 40 years. The leading
scientific theory at this time maintains that CJD and the other TSEs are
caused not by an organism but by a type of protein called a prion.

Prions occur in both a normal form, which is a harmless protein found
in the body's cells; and in an infectious form, which causes disease. The
harmless and infectious forms of the prion protein are nearly identical,
but the infectious form takes a different folded shape than the normal
protein. Sporadic CJD may develop because some of a person's normal prions
spontaneously change into the infectious form of the protein and then
alter the prions in other cells in a chain reaction.

Once they appear, abnormal prion proteins stick together and form
fibers and/or clumps called plaques that can be seen with powerful
microscopes. Fibers and plaques may start to accumulate years before
symptoms of CJD begin to appear. It is still unclear what role these
abnormalities play in the disease or how they might affect symptoms.

About 5 to 10 percent of all CJD cases are inherited. These cases arise
from a mutation, or change, in the gene that controls formation of the
normal prion protein. While prions themselves do not contain genetic
information and do not require genes to reproduce themselves, infectious
prions can arise if a mutation occurs in the gene for the body's normal
prions. If the prion gene is altered in a person's sperm or egg cells, the
mutation can be transmitted to the person's offspring. Several different
mutations in the prion gene have been identified. The particular mutation
found in each family affects how frequently the disease appears and what
symptoms are most noticeable. However, not all people with mutations in
the prion gene develop CJD. This suggests that the mutations merely
increase susceptibility to CJD and that other, still-unknown factors also
play a role in the disease.

CJD is not a contagious disease. Although it can be transmitted to
other people, the risk of this happening is extremely small. CJD cannot be
transmitted through the air or through touching or most other forms of
casual contact. Spouses and other household members of sporadic CJD
patients have no higher risk of contracting the disease than the general
population. However, direct or indirect contact with brain tissue and
spinal cord fluid from infected patients should be avoided to prevent
transmission of the disease through these materials.

In a few very rare cases, CJD has spread to other people from grafts of
dura mater (a tissue that covers the brain), transplanted corneas,
implantation of inadequately sterilized electrodes in the brain, and
injections of contaminated pituitary growth hormone derived from human
pituitary glands taken from cadavers. Doctors call these cases that are
linked to medical procedures iatrogenic cases. Since 1985, all human
growth hormone used in the United States has been synthesized by
recombinant DNA procedures, which eliminates the risk of transmitting CJD
by this route.

The appearance of the new variant of CJD (nv-CJD or v-CJD) in several
younger than average people in Great Britain and France has led to concern
that BSE may be transmitted to humans through consumption of contaminated
beef. Although laboratory tests have shown a strong similarity between the
prions causing BSE and v-CJD, there is no direct proof to support this
theory. Furthermore, BSE has never been found in the United States, and
importation of cattle and beef from countries with BSE has been banned in
the United States since 1989 to reduce the risk that it will occur in this
country.

Many people are concerned that it may be possible to transmit CJD
through blood and related blood products such as plasma. Some animal
studies suggest that contaminated blood and related products may transmit
the disease, although this has never been shown in humans. If there are
infectious agents in these fluids, they are probably in very low
concentrations. Scientists do not know how many abnormal prions a person
must receive before he or she develops CJD, so they do not know whether
these fluids are potentially infectious or not. They do know that, even
though millions of people receive blood transfusions each year, there are
no reported cases of someone contracting CJD from a transfusion. Even
among hemophiliacs, who sometimes receive blood plasma concentrated from
thousands of people, there are no reported cases of CJD. This suggests
that, if there is a risk of transmitting CJD through blood or plasma, it
is extremely small.

To reduce the already very low risk of CJD transmission from one person
to another, people should never donate blood, tissues, or organs if they
have suspected or confirmed CJD, or if they are at increased risk because
of a family history of the disease, a dura mater graft, or other factor.

Normal sterilization procedures such as cooking, washing, and boiling
do not destroy prions. Caregivers, health care workers, and undertakers
should take the following precautions when they are working with a person
with CJD:

Wash hands and exposed skin before eating, drinking, or smoking.

Cover cuts and abrasions with waterproof dressings.

Wear surgical gloves when handling a patient's tissues and fluids or
dressing the patient's wounds.

Avoid cutting or sticking themselves with instruments contaminated by
the patient's blood or other tissues.

Use disposable bedclothes and other cloth for contact with the
patient. If disposable materials are not available, regular cloth should
be soaked in undiluted chlorine bleach for an hour or more, then washed in
a normal fashion after each use.

Use face protection if there is a risk of splashing contaminated
material such as blood or cerebrospinal fluid.

Soak instruments that have come in contact with the patient in
undiluted chlorine bleach for an hour or more, then use an autoclave
(pressure cooker) to sterilize them in distilled water for at least one
hour at 132 - 134 degrees Centigrade.

A fact sheet listing additional precautions for healthcare workers and
morticians is available from the NINDS and the World Health
Organization.

Many researchers are studying CJD. They are examining whether the
transmissible agent is, in fact, a prion or a product of the infection,
and are trying to discover factors that influence prion infectivity and
how the disorder damages the brain. Using rodent models of the disease and
brain tissue from autopsies, they are also trying to identify factors that
influence susceptibility to the disease and that govern when in life the
disease appears. They hope to use this knowledge to develop improved tests
for CJD and to learn what changes ultimately kill the neurons so that
effective treatments can be developed.

Scientists are conducting biochemical analyses of brain tissue, blood,
spinal fluid, urine, and serum in hope of determining the nature of the
transmissible agent or agents causing Creutzfeldt-Jakob disease. To help
with this research, they are seeking biopsy and autopsy tissue, blood, and
cerebrospinal fluid from patients with CJD and related diseases. The
following investigators have expressed an interest in receiving such
material:

Health care workers who wish to receive information on special surgical
and disinfection procedures should see the NINDS Fact
Sheet for Healthcare Workers and Morticians or contact the NINDS Brain
Resources and Information Network (BRAIN) at:

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